Roman Emperor Marcus Aurelius Antoninus (121-180) was born on this day. His daily musings, Meditations, were transformed into the philosophy of stoicism, the ethics that laid the foundation for early Christianity.

Inspired by the Greek slave Epictetus' Discourses, Marcus Aurelius wrote of the importance of man being in tune with his inner nature and called that God dwelling within each of us, "fate."

"Our life is what our thoughts make it," he said, believing in free will and living simplistically.

Marcus Aurelius ruled at a time of war, conspiracy, and corruption. His diary, a collection of meditations and ideas, was never meant for publication. He wrote to help himself contemplate the right way to live. This great book of wisdom built his character and sustained him during his challenges.

With passion, he said, "Look within. Within is the fountain of good, and it will bubble up, if you ever will dig."

Marcus Aurelius believed in living with nature, in unity and order. With a philosophy similar to Taoism, he saw the external world as an interaction between opposites.

"Time is a sort of river of passing events, and strong is its current." he observed. "No sooner is a thing brought to sight than it is swept by and another takes its place, and this too will be swept away."

Stoicism is named after the mural-decorated porch, stoa poikele, which was found in Athens' Agora. Students would meet there to discuss ideas and search for the moral and intellectual perfection that made a person a sage.

"Do every act of your life as if it were your last," he wrote.

More MARCUS Aurelius Quotations

Happiness is within your power.